What are the required upload/download internet requirements to host your own server?

Recently i've go 300 symmetric connection finally after years of crappy dsl, and since there are no longer local servers being hosted in QL, I thought that I could host my own server with my own computer. Obviously it wouldn't be live 24/7, just when I want to play with some mates.

So what would be the requirements for a 6 slot server with no lag? is 300/300 enough? And also anyone got a tutorial in how to set the server up properly?

There should be a tutorial on the Steam QL commmunity. I think you'd need some knowledge of linux but am not certain. Perhaps someone who isn't in a hurry could direct you to the steam tutorial, even think there is one here on ESR but the Steam tutorial should be more active.